This invention relates to a paper feeding device for a collator.
In a conventional type of paper feeding device for a collator, a plurality of paper supply shelves are arranged in parallel spaced relationship with one another in a vertical direction and a stack of paper sheets to be collated is supported on each of the paper supply shelves so that the top sheet in the stack is successively removed from the stack. Feed rollers are disposed at the respective feeding stations in front of the paper supply shelves. Then during each collation cycle, a sequence of paper feeding operations which successively proceeds from the uppermost paper supply shelf through the lowermost paper supply shelf is performed by moving the suction heads between the upper surface of the top sheet in the stack and the feed rollers by a common drive mechanism at each paper supply shelf, so that the paper sheets are fed into the collator one by one from each paper supply shelf. Thus, in such drive mechanism, the respective suction heads of the paper supply shelves is not moved independently and then the suction heads of the uppermost paper supply shelf does not start the movement for the following paper feeding operation until the paper feeding operation by the suction heads of the lowermost paper supply shelf is finished. As a result the following collation cycle can not be started in proceeding a collation cycle.
On the other hand for the purpose of achieving a high speed collating operation, it is necessary to start the following collation cycle in proceeding a collation cycle. In order to this end, the drive mechanisms for the suction heads need being able to independently move the respective suction heads of the paper supply shelves in such a manner that the suction heads of the uppermost paper supply shelf starts the movement for the following paper feeding operation before the suction heads of the lowermost paper supply shelf finishes the paper feeding operation.
However, in the prior art, the drive mechanisms which can independently move the respective suction heads of the paper supply shelves is so complex that a larger space for containing such drive mechanisms is required.